In radio communication devices such as mobile telephones, carrier aggregation is used to deal with an increase in data traffic. Carrier aggregation is one of the technologies that perform radio communication in different bands at the same time. In a radio communication device supporting carrier aggregation, various communication circuits are provided, such as a front-end circuit that is an antenna-side transmitting and receiving end circuit.
Carrier aggregation often uses bands which are separated from each other, but nearby or adjacent bands may be used in the future. However, since communication bands are typically subdivided according to various circumstances of individual countries and telecommunications carriers, there are numerous combinations of nearby bands to account for in a carrier aggregating system. For example, if the front-end circuit were provided for each possible combination of nearby bands, the required circuit would increase in size.